Air conditioning system



R. V. WETZSTEON A-IR CONDITIONING SYSTEM May 5, 1942, y

Filed' Nov. 15, 1939 Patented lsy 5, 19421 UNITED STATESPATENT AOFFICE I l amcounrrrz'o sYs'rsM I Raymond V. Wetusteon, Butte, Mont. Application November 15, 1939, Serial No. 304,625

(ci. zar-s) comms.

This invention relates to air conditioning systems, and particularly to air conditioning units of the type in which room air is passed through a treating chamber or unit and then returned to the room.

The invention may be incorporated -in apparatus oi' any desired sizebut is particularly useful in the case of relatively small capacity in- Y stallatlons for dwellings, stores and theatres. ,Y An

objection to many of the present small air conditioning systems is the failure to maintain the desired room temperature when the demand fori' heat is well below the maximum capacity of the conditioning unit. The prior "onod" control systems resulted in an intermittent operation of the conditioning unit and the room temperature would overrun each time the conditioning unit was turned oil.V The interruptions of the air conditioning action were particularly objectionable when, as was customary, the air circulating ian was stopped when the room temperature was at or above the desired control point.

Une object of the present inventionis to provide an air conditioning system oi the separate conditioning unit type'A that includes control devices for .regulating the supply oi heating or cooling uid to the conditioning unit in accordance with the existing demand. An object is toprovide an air conditioning system including atrcating chamber, a heating coil in the treating chamber, a fan for passing room air through the chamber and returning` it -to the room, a control system for regulating the heat supply to the coil in accordance with the demand for heatA in the room,

and an additional control to prevent operation of I ,supply connection, and a three-way modulating valve under control of room temperature for regulating the relative quantities of boiler water and l of recirculated water that are supplied to the heating coil. Another object is to provide an air conditioning system, of the type last stated. in which the circulating pump andthe hot water boiler have a control system that is energized by the modulating valve when thelatter is adjusted, in response to the room thermostat, to supply heated 'water from the boiler to the conditioning unit coil. Y

These and other objects and advantages o1' the invention will be apparent from the following speciiication when taken with the accompanying drawing, in which:

Fig.' lis a schematic viewfof an embodiment i of the invention; and

Fig. 2 is a fragmentary schematic view of anK alternative control system for the air circulating fan and the humidiiler.

' In the drawing. the reference numeral i identifles the space or room Vfor which the air is to be conditioned by treatment in a chamber 42 that is connected to the room I by an inlet paag'e 3 and return passage il. A circulating fan 5 is located in the conditioning chamber, or one of? the pa's- I sages, and its motor 8 may be' within the path 'of 'the air stream or, as illustrated, at the exterior oi the air passages and chamber. A humidifier 8, preferably oi the spray nozzle type, is located in the chamber beyond the heatexchanger 2 and is controlled by an electrically operated valve s.

The heat exchanger is connected to a hot water boiler It by a supply conduit II and return conduit I2 that includes a circulating pump I3 and check valve lo. A by-pass conduit I5 er.-

tends from the retum conduit I2; at a point begressive lthrottling-of the hot water inlet to the valve.

The modulating valve I6 is versible motor I'I that is controlled, in known manner, by a modulating thermostat T in the room I, anda bridge network and balanced relay, not shown in detail, in the box I 8. The motor and the bridge network of this modulating control system are energized from an alternating current power line I9 through the transformer 20.

The supply of fuel to `the boiler I0 is controlled automatically but the particular type of fuel is not important as automatic controls are known for boilers of the gas, oil or coal iired type.

For simplicity of illustration, a. fuel supply conduit 2l under control of an electricaldevice 22 is shown in Fig. l. The circuit of the control device 22 includes a transformer 23 that is connected across leads 24, and a temperature-controlled switch 25 that responds to the temperature of the waterwithin the boiler I0. The switch 25 adjusted by a rev may be a normally closed "high limit" switch that opens when the water temperature exceeds a selected value.' or a normally open lowlimit" switch that closes to complete the energizing cir- .cuit for the device 22 when the'water tempera-` l position by the motor I1 when the modulating valve I6 isadjusted to open, or partially open, the supply conduit II to the heat exchanger "I of the conditioning chamber. The controlled circuit leads 24 supply energy to the motor 28 of the water circulating pump I3 and, through a temperature-controlled switch 3c, to the fan motor 6 and to the transformer 3i of the humidity control circuit that includes the electrically operated valve 9 and' a room humidistat H. The actuating element of the switch 30 is located in the return conduit I2, and adjacent the heat exchanger 1; the switch 30 being so adjusted that it does not close untilhthe treating chamber temperature, as reflected in the' exit temperatureof the circulated heating iluid, rises to a selected value.

For cooling in summer, the cold water inlet pipe 'II' and exhaust pipe 'I2' are connected to the conduits I I, I l, respectively, and manually operable valvesv 33 are included in conduits it, I2 and pipes II', I2 for connecting the appropriate iluid supply system to the heat exchanger 2. The cold water pipe II may extend to a deep well or to a refrigerator system.

The operation of the system is as follows. Assuming that the thermostat- T has just been adjusted, either manually or byv known clock mechanism; from a night temperature of 50 to a day temperature of 70. This change'in the setting of the thermostat T results in an energization of the motor I'I to move the modulating valveV I6 into the fully open position shown in Fig. l, and also closes the relay switch 28 to connect the controlled leads 24 to the power line I.

` The water circulating pump I3 is thus placed in operation and the furnace controls are energized.

The fan 5 and humidifier 8 are not placed in operation until the return water temperature rises to such a -value that the circulationA of air through the room I will not produce cold drafts.

The room temperature rises as soon as the fan 5 is in operation and, as the temperature approaches the desired control point, the motor I1 is brought into operation by the ,modulating thermostat T to move the modulating valve I6 clockwise. This results in the recirculation of a part of the return water from the heat exchanger and thus lowers the4 rate of heat supply to the conditioning chamber. The supply of heat to the room I thusr decreases progressively as the room temperature approaches the selected control point. The air conditioning system will thus i the cooling water system at say 80,

aaa'aois the air temperature within the conditioning chamber 2. This form of control circuit includes a thermostatic member such as a Sylphon bellows 30a within the chamber 2 for operating a mercury switch 30h to closed circuit position when the chamber temperature rises to a selected value that will prevent cold drafts. l

. For summer cooling, the valves 33 are adjusted to connect the cold water pipe system II', i2 to the heat exchanger, and the furnace control circuit is opened manually. A cooling thermostat operates through relays to turn on the air circulating fan at say '18 and to start a pump in If desired, the exit cold water pipe I2 may be connected to the hot water return pipe I2 between the check valve I4 and the boiler I0, thus permitting a i control of the rate of `cooling by the modulating.

valve It.

It is to be understood that the invention is not limited `to the particular constructions herein shown and described as different parts of the control system may be modified, if necessary or desirable, in accordance with the particular structure of the boiler and its type of control. The boiler control device 22 may be an electromagnetic valve when the fuel is gas, or a motor when oil or coal is used.

I claim: 1. In an air conditioning system, the combina.-

tion with a conditioning chamber, a heat exchanger within the chamber, and passages connecting said chamber with a room fo'r which the air is to be conditioned, of a fan for establishy ing a flow ci' air from said room through the conditioning chamber and b'ack to the room, a hot water boiler. supply and return conduits connecting said heat exchanger to-the boiler, a .,circulating pump in one of said connections,

means including a Amodulating valve in the supply conduit and a thermostat in the room for remain in continuous operation for long periods under normal conditions and the tendency towards overrunning of the temperature is substantially eliminated.

As shown in Fig. 2, the operation of the fan regulating the rate of heat supply from the boiler to the heat exchanger in accordance with the room temperature, and an electrical control system for said fan and said pump. said control system including a switch actuated by said modulating valve.

2. In an air conditioning system, the invention as claimed in claim 1, wherein saidmodulating valve is a three-way valve. and a by-pass conduit extends from said valve to the return conduit, whereby water from said heat exchanger may be mixed with hot water from the boiler and returned to the heat exchanger.

3. In an air conditioning system, a conditioning chamber, a heat exchanger within said chamber, a fan for establishing a stream of air through said chamber and into the space for which the air is to be conditioned, means controlled by temperature changesvwithin said space for supplying to said heat exchanger hot water at a temperature that varies with the departure of the space temperature from a preselected value, and a control circuit for said fan including a switch for delaying the energlzation of said fan until the temperature within said conditioning chamber reaches a preselected value.

4. In an air conditioning system, the invention as claimed in claim 3, wherein said switch includes an operating member subject to the temperature of the water leaving said heat exchanger.

5. In an air conditioning system, the invention as claimed in claim 3, wherein said switch includes an operating member subject to the temmascia perature of the air within said conditioning chamber.

6. In an air conditioningsystem, lthe combination with a heat exchanger, a hot water boiler, conduite connecting said heat exchanger and boiler, and a pump in one of said conduits for circulating water from the boiler throughsaid heat exchanger, of means for adjusting the ow ot water from the boiler to the heat exchanger, said means including a modulating valve in one of said conduits and a by-pass extending from said valve to the other conduit. a thermostat in the space to be heated for actuating said modulating valve, and relay means including a switch actuated by said modulating valve for energizing said pump and controlling the fuel supply to said boiler.

RAYMOND V. WETZSTEON. 

